Time to go on the record: Is this going to be the year?

[XemaSab]

Is the ice going to go under 1 million square kilometers?

11 votes, 0 passes | Time left: Unlimited
	Yes
	5 (45%)
	No
	5 (45%)
	I like threadjacking!
	1 (9%)
	0 DU members did not wish to select any of the options provided.
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[Systematic Chaos]

1. I vote no, but it will go lower than 2012 and get pants-shittingly close.

[joshcryer]

2. I had doubts last year it would go as low as it did.

Boy was I wrong.

[phantom power]

3. interesting, we're exceeding 4/5 'yes' votes

(and one vote for pants-shittingly-close, who we might caucus with)

[GliderGuider]

4. And here I thought I was a doomer!

No, I don't think we'll see 1M this year. We may see a break below 2 million, but my guess is in a range of 1.75 to about 2.1 (assuming we're talking about CT area).

[Dead_Parrot]

12. ^ What he said. nt

[OakCliffDem]

5. It is going to be a jaw dropping summer

When the ice extent starts setting record lows in August, there will be all kinds of scientific explanations about natural variability and what have you.

When the extent drops below 2 million square kilometers, there will be gasping and groaning about a once in 1000 year lows.

When it kisses the 1 million mark, the deniers will will be completely silent.

[OnlinePoker]

6. Since it's happened before without man's influence, no. n/t

[CRH]

7. I think it could go below 1.5 million sq/km ...

last year it bottomed at 3.41 km/sq. But my prediction would be higher in the 2 to 2.25 range.

If it goes below 2 million km/sq then to my mind the certainty is accented that the of the worst scenarios of runaway warming are well advanced. Which translates to not much time before the escalation to 4*C then 6*C by end of century.

My log on screen will be changed to the PIOMASS site at the equinox with the first days of 24 hour sun. By July/August the ice volumes k/m3 will tell us more of the story than the extent.

I hope for the best, but am tempered by probabilities.

I think 2014 - 2015 are the years most likely the planet breaches the 1 million k/m/sq.

[muriel_volestrangler]

8. 3.41m sq.km was the min. extent in 2012; I think most people are talking area

which had a minimum of 2.23m sq.km. My guess for area is about 2 million sq. km - it seems to be that the last couple of big decreases in a single year have been followed by a year or 2 at not much worse than before.

[CRH]

9. Agreed, I think between 2.25 and 2 million sq/km ...

and it has been the pattern that years after big melt have been slower.

You have a good background in science, maybe you can help. Is the logic in the following correct, or no.

For me the PIOMAS km3 (volume) is more important, because it is a more accurate determination of old ice. The elevating temperatures of arctic water can reduce the volume at a faster rate than the decline of extent. Cloudy days might hinder a rapid loss of extent, but below the water surface the rate of ice failure might actually increase. The two measurements might not be in proportion. -- Less ice volume represents more existing temperature than might be represented by ice extent. Once the ice fails, with it the thermal inertia decreases and more rapid increase in water temperature will happen, not just from albedo, but the physics as well. Is this accurate?

[muriel_volestrangler]

10. I agree volume is important

though what is important depends on what you're considering. The amount of old ice does seem important when considering what each year's minimum will be - we're at the stage in which pretty much all ice formed since the last year's minimum is bound to melt during the summer, and the question is how much multi-year ice will go too, and the volume gives us a good idea of what goes each year. Yes, you're right that warmer water (eg from currents from the Atlantic or Pacific) can reduce the volume even if the area isn't decreasing significantly.

For some things, the measure of the area may still be more 'important', though - for instance, in the feedback due to albedo. It doesn't matter how thick the ice is for that, it's just how much sunlight it reflected back by the surface. And that actually means weighting the area figures according to the sunlight reaching the surface, which is most in high summer, with hours of daylight and the angle the sun is in the sky, and the latitude the ice is at (and cloud cover, though that's going to be harder to allow for).

Luckily, the mathematician 'tamino' (I forget his real name) who write the 'Open Mind' blog has done some calculations for this, up to and including 2011 (not trying to include cloud cover, and modelling Arctic sea ice as a perfect circle, and Antarctic as a perfect ring): http://tamino.wordpress.com/2012/10/01/sea-ice-insolation/

average annual insolation:



For your final bit ("Once the ice fails, with it the thermal inertia decreases and more rapid increase in water temperature will happen, not just from albedo, but the physics as well&quot - yes, I think that would happen in the surface layer. However, water mixes, so there's the potential for the extra heat to be spread far further down than it is with ice. You'd need someone who understands the dynamics of ocean warming to explain what people think happens to temperatures (and at what depth) when ice cover goes.

[CRH]

11. Thank you for your input, added perspective, ...

And links to further understanding. hrh